I currently have the DPF & NOX deleted with an H&S DPF delete package. I still have the CAT in the OEM downpipe. I'm looking at removing the H&S and installing the Flo-Pro Stage II system, in stainless steel, which includes the DPF & NOX delete in addition to the CAT delete (downpipe).

Question #1...Is the cat in the downpipe that restrictive? My truck has a relatively nice "rumble" to it without being an annoyance. I assume, if unleashed, the 6.7 will be as loud (or louder) than a straight-piped 5.9 after the inclusion of the CAT delete.

Question #2...Will I see much of a performance gain in deleting the CAT in the downpipe? I have achieved a solid 18.3 mpg (hand calculated) on a trip to Panama City Beach, FL last summer. The truck has plenty of power stock (I do have a Juice w/Attitude (#6 HOT unlock) and barely use it over Level 1 or Level 2......unless I have some pesky ricers nearby. I am essentially looking to squeeze a little more fuel economy out of the Blue Bus. The EGR is still in place, by the way. It currently has 34.5k miles on the clock.

Question #3....For those that have the Stage II setup, do any of you run the Donaldson or Nelson mufflers?

Sorry for so many questions.....just trying to do my research before I take the plunge.

Thanks in advance for your responses.....

Greg

 

Nah.. Even with my 4" turbo back to 5inch stacks its not as loud as you would think. I find its a good bit quieter than a 5.9. It does go to resonating around 2100 rpms and will drone some, but I dont mind.